Semiconductor devices are manufactured using various processes including photolithography processes, thin-film deposition processes, and etching processes. Photolithography processes, which may determine a minimum line width or a critical dimension (CD) of a semiconductor device, may include coating a photoresist layer on a substrate, exposing the photoresist layer to light, and developing the photoresist layer. Photomasks including photomask patterns may be used when a photoresist layer is exposed to light. Photomask manufacturing processes may cause variations in spaces between photomask patterns and variations in directions of the photomask patterns, and thus the photomask patterns may have registration errors.